CS 497C Introduction to UNIX Lecture 18: The GNU emacs Editor

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CS 497C Introduction to UNIXLecture 18 - The
GNU emacs Editor

• Chin-Chih Changchang_at_cs.twsu.edu

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Deleting, Moving and Copying Text

• To delete a character, use Ctrl-d. To delete a
  word, use Alt-d.
• To delete text from the current cursor position
  to the end of line, use Ctrl-k.
• To delete the entire line, first use Ctrl-a and
  then Ctrl-kCtrl-k.
• To delete text in a region, first mark the region
  and then use Ctrl-w.

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Deleting, Moving and Copying Text

• Ctrl-y is universally used to restore text from
  the deletion.
• While Ctrl-w deletes text in a region, the
  command to copy text is Alt-w.
• You can transpose two adjacent characters by
  using Ctrl-t.

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Changing Case of Text

• To convert an entire word to uppercase, move to
  the beginning of the word and then press Alt-u.
• You use Alt-u for converting a word to
  lowercase.
• To capitalize a single character, position the
  cursor under it and then use Alt-c.

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Changing Case of Text and Command Completion

• For transforming case in large blocks of text,
  use a region. The commands to convert text in a
  region are Ctrl-xCtrl-u and
  Ctrl-xCtrl-l.
• The command completion feature can reduce some of
  the typing work.
• The guiding principle here is this Enter as much
  of the command text as you want and then press
  the Tab key.

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Undoing and Redoing Editing

• To undo the change, there are three ways
  Ctrl-xu, Ctrl-_, Ctrl--.
• If you continue to press Ctrl--, youll undo
  the changes made before the last save.
• If you keep pressing Ctrl--, emacs starts
  redoing everything that you have undone.

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String Search

• The incremental and non-incremental search
  techniques are used in string search in emacs.
• Incremental search is invoked with Ctrl-s
  followed by the search string.
• After entering Ctrl-s emacs prompts for the
  search string in the minibuffer. Suppose youre
  looking for mail. After m is entered, the search
  starts immediately.

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String Search

• The cursor relocates itself at the first instance
  of m maybe on the word moon.
• After mail is entered, press Enter.
• There are a number of advantages of using
  incremental search
• The search is faster.
• emacs tells you instantly whether the string
  exists in the file.
• If there is a typo, backspacing erases the error.

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String Search

• At the end of a file, use Ctrl-r instead of
  Ctrl-s.
• To repeat a search, youll have to use the same
  command Ctrl-s or Ctrl-r.
• In non-incremental search just press Enter and
  then type the string.
• Like vi, emacs uses a pattern comprising some
  special characters to look for similar strings.
  This pattern is called a regular expression.